It is common to display samples of sheet materials such as placards, flooring, carpeting, paneling and the like in display frames that hold one or more sheets of the material such that the material can be easily examined by a potential purchaser.
Typically, such devices comprise a rectangular supporting frame having four edge members. Typically three of the edge members ("the channel edges") comprise U-shaped channels and the fourth edge member ("the slotted edge") has an access slot into which the sheet material is inserted. The resulting structure "frames" the sheet-material so that a potential purchaser, for example, can touch the sheet material for evaluation. Examples of such display frames can be found in U.S. Pat. No. 5,442,873 to Vogler and U.S. Pat. No. Des 381,834 to Potter et al.
A series of the frames are often mounted on hinges or pivot pins and placed in a rack so that a plurality of the frames, with the sheet material inserted therein, can be flipped through by the consumer when conducting the evaluation. Examples of rack mounted display frames are found in U.S. Pat. No. 3,924,749 to Weston; U.S. Pat. No. 1,116,484 to Ralph; and U.S. Pat. No. 3,181,706 to Mandel.
Certain problems exist with the prior art display frames. The access slot in the slotted edge must be wide enough for insertion of the sheet material into the U-shaped channels of the remaining three channel edges. As a result, when the display frames are moved by the potential purchaser, there is a tendency for the sheet material to slide out through the access slot. Further, if a large page-frame is used to display a large piece of sheet material, the weight of the material bears down on the frame when it is oriented vertically and can cause deformation of the frame.
Attempts have been made at avoiding the problem of having the sheet material slide out of the frame. U.S. Pat. No. 2,981,018 to Hopp et al. teaches the use of a "spring finger" attached at one end of U-shaped channels that form the frame. The spring finger is located adjacent the open end of the channels proximate to the open (slotted) edge of the frame. The spring finger is biased to contact the corner of an inserted placard and essentially blocks the insertion slot to hold the placard in place. The extreme end of the finger projects through the slot of the frame so that it can be pushed out of the way to release the spring pressure and free the placard for removal from the frame or to allow a placard to be inserted into the frame.
Although this is an improvement over prior frames which make no accommodation for slippage of the sheet material, this still requires special assembly of the spring finger which is a costly additional manufacturing step.
Various other patents teach slotted holders in which projections project into the slotted edge for engaging the displayed placard/sheet. The Vogler patent discloses nibs or tooth-like projections extending inwardly into and bridging the opening of the slotted edge of the frame. The nibs are formed on at least one of the two strips that define the slotted opening, and they are of a thickness such that a nib on one strip will make contact with the opposite strip, thereby holding the placard in the frame. Vogler utilizes the tendancy of the strips to normally "flex slightly toward one another" to enable the thickness of the nibs to be "slightly less" than the width of the slot opening. However, the projections into the opening of the frame disclosed in Vogler still reduce the space into which the sample can be inserted by placing an impediment in the insertion path of the sample.